Pros

Pro

Amazing IDE support

Since Kotlin is made by Jetbrains (the developers of IntelliJ IDEA) so it stands to reason that the IntelliJ support for Kotlin is also great.

Pro

Java interoperability

Since it runs on the JVM, Kotlin is 100% interoperable with Java and can use existing Java frameworks and libraries.

Pro

Easy to learn if you have prior programming experience

Kotlin's syntax is extremely easy to understand. The language can be picked up in a few hours just by reading the language reference.

Pro

No runtime overhead

Because the standard library is pretty small and tight, it mostly consists of focused extensions of the Java standard library.

Cons

Con

May be hard for programmers already used to imperative style to learn functional programming from Kotlin

Since Kotlin does not enforce any particular paradigms and is not purely functional, it can be pretty easy to fall back to imperative programming habits if a programmer comes from an imperative background.